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27 Cards in this Set

what specific bond is associated with branching on a glycogen molecule?

alpha-1,6-glycosidic bond

branching on a glycogen molecule occurs at approximately every ______ glucose monomers.

8 to 14

in the first step of glycogen synthesis, glucose-1-P goes to UDP-glucose via what enzyme and cofactor?

UDP-glucose pyrophosphorylase and UTP

are the 2 Phosphates on UDP-glucose both from UTP?

No, one is from UTP and the other remains from glucose-1-P.

what, self-glycosylating, protein forms the initial glucose monomer chain from which glycogen can be formed?

Glycogenin

what enzyme acts to add UDP-glucose to the growing glycogen chain?

glycogen synthase

is UDP-glucose added to the non-reducing or reducing end of the glycogen template?

non-reducing end

what action the the 'branching enzyme' perform? be specific

-a 7 segment section is transferred from the non-reducing endof a chain to the C6-hydroxyl group on the same or another glycogen molecule.
-every segment transferred comes from a chain at least 11 residues long.
-branching point must be at least 4 residues from all other branches

In regards to glycogen degredation, what are the yeilded percentages of glucose-1-P to free glucose?

-first, the enzyme transfers the last three residues on the branch chain to the non-reducing end of another glycogen molecule.
-then, the enzyme cleaves the alpha-1,6-glycosidic linkage to yeild free glucose + debranched glycogen.

How many active sites does the 'debranching enzyme' have?

2 active sites

what are the allosteric effectors of 'glycogen phosphorylase'? how do they effect the enzyme?

activator: AMP, (phosphorylation)

inhibitors: ATP, Glucose-6-P, free glucose.

what are the allosteric effectors of 'glycogen synthase'? how do they effect the enzyme?

activators: ATP, liver glucose, gucose-6-P.

inhibitor: (phosphorylation)

glucogon binds to a cell surface receptor protein which is a member of a group of proteins called, _____.

G-proteins

the G-protein receptor of glucagon activates what enzyme?

adenylate cyclase

adenylate cyclase aids in the synthesis of what molecule?

cyclic-AMP

what group of proteins does cAMP phosphorylate and activate?

"cAMP dependant protein kinases"

cAMP dependant protain kinases phosphorylate and activate what two enzymes?